In U.S. Pat. Nos. 3,595,232; 3,734,351; 3,780,732; and 4,187,847, among others, apparatus for the pressure infusion of blood and parenteral solutions is disclosed. Pressurized infusion of parenteral solutions and blood is desirable in some circumstances, since the infusion can be performed independent of gravity, for example when the infusion must be performed at an accelerated rate under emergency conditions.
Also, the Fenwal Division of Baxter Travenol Laboratories, Inc. sells a pneumatically inflatable pressure cuff for surrounding a blood bag and pressurizing it so that blood may be administered from a blood bag within the pressure cuff at a greatly accelerated rate by pneumatic pressurization of the cuff, for example in the instance of a patient with a severe hemorrhage.
However, in the prior art, pressure infusion devices have been expensive and cumbersome, utilizing springs and pressure plates, or requiring pneumatic pumps and the like. There is a need for inexpensive, compact pressure infusion devices which can be stored in the scarce space of an ambulance or a field hospital, since one major desirable use of gravity-free pressure infusion systems is in areas away from the hospital such as on the battle field. Similarly, at the site of an accident, where blood and parenteral solutions must be administered under non-clinical conditions, for example in a moving ambulance, it may be inconvenient to elevate the liquid material for administration to take advantage of conventional gravity flow administration.
Furthermore, there is a need for a convenient, simple, inexpensive, and preferably wearable system for administering small amounts of critical medications over a period of hours while the patient is ambulatory. For example, a diabetic patient may desirably be administered insulin on a generally continuous basis over a 24-hour period, with a total of about 5 mil., for example, being administered. Such a continuous administration of insulin more closely simulates the physiology of the normal functioning of the pancreas in the healthy individual.
Similarly, it is generally agreed that it would be desirable in numerous circumstances to administer a small amount of medicament on a continuous basis over a 24-hour period if it can be conveniently done while the patient is ambulatory. Specifically, continuously administered heparin and other medicament are disclosed in the article by Blackshear in the December, 1979 issue of Scientific American, pages 66 to 71.
In accordance with this invention, an optionally wearable module for pressure administration of liquids is provided for the administration of small amounts of medicament over a period of hours, or for the administration of any fluid material in medical or other fields, including liquids or gases as may be desired. The simple pressure administration module may be of about the size of a deck of cards and adapted to administer only a few cubic centimeters of medicament over a period of hours. Alternatively, if desired, an administration module in accordance with this invention may be utilized which contains a liter or more of solution, for accurate administration of parenteral solutions in a manner independent of gravity.